Ecosystem Interactions

Overview

Students explore how organisms in ecosystems interact, focusing on cause-and-effect relationships (dependence, competition, predation, and mutual benefit). They use scenario cards and diagrams to identify relationships and explain how changes in one population can affect others.

Learning intentions

• Students will explain relationships between two or more organisms using evidence from scenario cards.
• Students will classify interactions as predation, competition, mutual benefit, or dependence on shared resources.
• Students will describe possible effects when one population changes (for example, insects disappearing from a meadow).
• Students will participate in collaborative discussions by building on others’ ideas and communicating clearly.

Success criteria

• I can identify the organisms involved in an ecosystem scenario.
• I can state the relationship type (predation, competition, mutual benefit, dependence on shared resources) and why.
• I can describe how one organism or population affects another using evidence from the cards.
• I can work respectfully with my group and share our reasoning.

Curriculum links

• Reading: Informational Text — Explain relationships or interactions between individuals, events, ideas, or concepts in a text using specific information.
• Speaking and Listening — Engage effectively in collaborative discussions, building on others’ ideas and expressing ideas clearly.
• Writing — Introduce a topic clearly and organize related information logically to support understanding.
• Reading: Informational Text — Read and comprehend informational texts independently at an appropriate complexity level (applied through today’s scenario analysis).

Lesson structure (45 minutes)

1. 0–5 min · Hook question. Teacher displays the question: “What might happen if all the insects disappeared from a meadow?” and reminds students of the goal: relationships in ecosystems. Students think independently for 30–45 seconds, then discuss with a partner and prepare one reason.

2. 5–10 min · Whole-class share. Teacher calls on 3–4 pairs and prompts: “What evidence from the scenario or your science knowledge supports that?” and “How might that affect other organisms?” Students share respectfully, listening to different perspectives and adjusting ideas when appropriate.

3. 10–18 min · Introduce interaction types. Teacher briefly models key relationship examples using diagrams/pictures:

• Predation: a hawk eating a mouse
• Mutual benefit: bees pollinating flowers
• Competition: two plants competing for sunlight
• Dependence on shared resources: animals relying on the same water sources Teacher emphasizes: organisms depend on other organisms, compete for resources, may benefit from relationships, and can be affected by changes in other populations. Students turn and talk after each example: “Which two organisms are interacting, and what is the relationship?”

4. 18–25 min · Guided practice model. Teacher selects one scenario card and models a quick analysis using a graphic organizer/chart:

• Organisms involved
• Relationship type
• Resources involved
• Possible effect if something changes (population change or resource change) Teacher thinks aloud: “If the resource or population changes, what happens next?” Students help fill in one chart entry at a time (quick, low-stakes responses).

5. 25–35 min · Group sort (collaborative practice). Teacher places students into groups of 3–5 and gives each group a set of ecosystem interaction cards, a group recording sheet, and relationship chart categories. Students sort cards into categories, discussing reasoning until the group agrees, and record at least one sentence for each classification using evidence from the cards.

6. 35–40 min · Group share. Teacher invites each group to select one scenario to explain. Students present using the structure: “The ___ affects the ___ because ___,” pointing to the scenario details.

7. 40–45 min · Individual written response + exit ticket. Teacher distributes the individual response worksheet and exit ticket prompt: “Describe one way that two organisms can affect one another.” Students write a short response; teacher collects worksheets and exit tickets for quick review.

Resources

• Ecosystem interaction scenario cards (examples of predation, competition, mutual benefit, shared resources)
• Organism interaction diagrams or pictures (hawk-mouse, bee-flower, plant-sunlight, animals-water)
• Relationship chart categories (Predation, Competition, Mutual Benefit, Shared Resources/Dependence)
• Group recording sheet (cards sorted + short justification sentence)
• Individual response worksheet (short constructed response)
• Exit ticket slip
• Timer and teacher checklist for anecdotal notes
• Sentence frames (optional): “The ___ affects the ___ because ___.”

Assessment

• Formative (during sorting): Teacher anecdotal notes on participation, communication, and collaboration.
• Formative (during discussion): Listen for students using scenario evidence to explain relationships.
• Summative (end-of-lesson writing): Individual written response to describe how two organisms affect each other.

Differentiation

• Support: Provide sentence frames (“The ___ affects the ___ because ___.”) and a partially filled relationship chart for students who need structure.
• Visual support: Offer color-coded card sets and example diagrams for each interaction type.
• Collaboration support: Assign roles (materials manager, reader, evidence checker, speaker) within groups to ensure every student contributes.
• Modification: Allow oral responses instead of written for students who need it; capture oral reasoning using teacher notes.

Homework

• Students observe or research one example of two organisms interacting and record: the organisms involved, the relationship type, and one possible effect of a change.